// 把函数指针放入一个数组中存起来
int Add(int x, int y)
{
    return x + y;
}
int Sub(int x, int y)
{
    return x - y;
}
int Mul(int x, int y)
{
    return x * y;
}
int Div(int x, int y)
{
    return x / y;
}
int main()
{
    int (*pf)(int, int) = Add;
    int (*ppf_arr[4])(int, int) = {Add, Sub, Mul, Div}; // ppf_arr 就是函数指针数组
}